U.S. colleges saw drops in undergraduate enrollment for this year’s spring semester as the emergence of Covid-19 vaccines failed to bring more students back to campus, deepening the pandemic-related financial strains faced by schools.

Enrollment fell 4.5% from with a year ago, according to data released Thursday by the National Student Clearinghouse Research Center. The largest declines included 16% for international students, 9.5% at community colleges and 5.3% for students of the traditional age of 18 to 24. Fewer undergrads attended in all racial and ethnic categories.

“There’s no quick turnaround in sight for undergraduate enrollment declines driven by the pandemic,” said Doug Shapiro, the group’s executive director. Community colleges tend to serve more low-income students, who have been among the most affected by the pandemic, he said.

Just about a year after schools sent students home to prevent the spread of the Covid-19 virus, colleges are hoping to re-establish normalcy and stabilize their revenue. They’ve lost money from canceled summer events and empty dorms, while fundraising has been flat and endowment returns have plunged.

Overall college enrollment is 2.9% below last spring’s level. One bright spot was an increase in graduate enrollment, up 4.3% year over year.

The data for undergrads suggests that students may have been frustrated with the limited fall semester experience and held off on the spring classes, said Willis Jones, an associate professor at the University of South Florida who focuses on higher education finance and policy. Most colleges held some form of online classes and those with in-person instruction often imposed a restrictive environment to keep students safe.

“The question is, ‘Will they come back this fall?’ ” Jones said. “If history is any indication, higher ed has a tendency to bounce back, though this is unprecedented.”

A bounce-back could be already showing in admission data. Selective colleges have seen large increases in appliations for the fall term, including a 42% jump at Harvard. The surges can be partly attributed to many schools dropping standardized testing requirements.

Overall, application volume increased by 11% from the previous year through March 1, according to the Common Application, which allows students to apply to multiple colleges at once.

This article was provided by Bloomberg News.